Smallest and Largest Planets in the Solar System By: Maria Temming | July 15, 2014 There are a couple of different ways to measure how “big” something is. The first is an object’s mass (how much matter it contains) and the second is its volume (how much space it takes up). The smallest and largest planets in our solar system are Mercury and Jupiter , respectively. The smallest planet in regards to both mass and volume is Mercury —this tiny world is nearly 20 times less massive than Earth, and its diameter is about times 2 ½ smaller. In fact, Mercury is closer in size to our Moon than to Earth. The largest planet in our solar system by far is Jupiter, which beats out all the other planets in both mass and volume. Jupiter’s mass is more than 300 times that of Earth, and its diameter is about 11 times larger than Earth’s diameter. (Jupiter's Great Red Spot, even at its current diminished size , spans 15,900, just over a full Earth diameter.) Jupiter is 2 ½ times more massive than the rest of the planets in the solar system combined.

A size comparison of the planets in our solar system. In order of increasing distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. NASA Lunar and Planetary Institute Learn more about our solar system's most ostentatious planet — the ringed giant Saturn and its fascinating family of moons — in our FREE ebook, Saturn's Bounty . Enter your email address to download the ebook, and you'll also receive our weekly e-newsletter with the latest astronomy news. * What is the third largest planet? | Reference.com What is the third largest planet? A: Quick Answer The third largest planet in our solar system is Uranus. It has a diameter of almost 30,000 miles, which is more than three and a half times the size of Earth. Full Answer Uranus is the seventh planet from the sun and takes about 84 Earth years to complete an orbit. It is considered one of the four gas giants, along with Jupiter, Saturn and Neptune, because it is composed entirely of gas. William Herschel used a telescope to identify Uranus as a planet in 1781.

The planet is unusual in that its axis is tilted at 98 degrees, causing it to rotate on its side. Uranus has 27 moons and at least 13 known rings. What are the Planets of the Solar System? - Universe Today Universe Today What are the Planets of the Solar System? Article Updated: 21 Aug , 2016 by Matt Williams At one time, humans believed that the Earth was the center of the Universe; that the Sun, Moon, planets and stars all revolved around us. It was only after centuries of ongoing observations and improved instrumentation that astronomers came to understand that we are in fact part a larger system of planets that revolve around the Sun. And it has only been within the last century that we’ve come to understand just how big our Solar System is. And even now, we are still learning. In the past few decades, the total number of celestial bodies and moons that are known to orbit the Sun has expanded. We have also come to debate the definition of “planet” (a controversial topic indeed!) and introduced additional classifications – like dwarf planet, minor planet, plutoid, etc. – to account for new finds.

So just how many planets are there and what is special about them? Let’s run through them one by one, shall we? Mercury: As you travel outward from the Sun, Mercury is the closest planet. It orbits the Sun at an average distance of 58 million km (36 million mi). Mercury is airless, and so without any significant atmosphere to hold in the heat, it has dramatic temperature differences. The side that faces the Sun experiences temperatures as high as 420 °C (788 °F), and then the side in shadow goes down to -173 °C (-279.4 °F). MESSENGER image of Mercury from its third flyby. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington Like Venus, Earth and Mars, Mercury is a terrestrial planet, which means it is composed largely of refractory minerals such as the silicates and metals such as iron and nickel. These elements are also differentiated between a metallic core and a silicate mantle and crust, with Mercury possessing a larger-than-average core.

Multiple theories have been proposed to explain this, the most widely accepted being that the impact from a planetesimal in the past blew off much of its mantle material. Mercury is the smallest planet in the Solar System, measuring just 4879 km across at its equator. However, it is second densest planet in the Solar System, with a density of 5.427 g/cm3 – which is the second only to Earth. Because of this, Mercury experiences a gravitational pull that is roughly 38% that of Earth’s (0.38 g). Mercury also has the most eccentric orbit of any planet in the Solar System (0.205), which means its distance from the Sun ranges from 46 to 70 million km (29-43 million mi). The planet also takes 87.969 Earth days to complete an orbit. But with an average orbital speed of 47.362 km/s, Mercury also takes 58.646 days to complete a single rotation. Combined with its eccentric orbit, this means that it takes 176 Earth days for the Sun to return to the same place in the sky (i.e.

a solar day) on Mercury, which is twice as long as a single Hermian year. Mercury also has the lowest axial tilt of any planet in the Solar System – approximately 0.027 degrees – compared to Jupiter’s 3.1 degrees, which is the second smallest. The MESSENGER spacecraft has been in orbit around Mercury since March 2011 – but its days are numbered. Credit: NASA/JHUAPL/Carnegie Institution of Washington Mercury has only been visited two times by spacecraft, the first being the Mariner 10 probe, which conducted a flyby of the planet back in the mid-1970s. It wasn’t until 2008 that another spacecraft from Earth made a close flyby of Mercury (the MESSENGER probe) which took new images of its surface , shed light on its geological history , and confirmed the presence of water ice and organic molecules in its northern polar region. In summary, Mercury is made special by the fact it is small, eccentric, and varies between extremes of hot and cold. It’s also very mineral rich, and quite dense!

Venus: Venus is the second planet in the Solar System, and is Earth’s virtual twin in terms of size and mass. With a mass of 4.8676×1024 kg and a mean radius of about 6,052 km, it is approximately 81.5% as massive as Earth and 95% as large. Like Earth (and Mercury and Mars), it is a terrestrial planet, composed of rocks and minerals that are differentiated. But apart from these similarities, Venus is very different from Earth. Its atmosphere is composed primarily of carbon dioxide (96%), along with nitrogen and a few other gases. This dense cloud cloaks the planet, making surface observation very difficult, and helps heat it up to 460 °C (860 °F). The atmospheric pressure is also 92 times that of Earth’s atmosphere, and poisonous clouds of carbon dioxide and sulfuric acid rain are commonplace. Venus’ similarity in size and mass has led to it being called “Earth’s sister planet’.

Credit: NASA/JPL/Magellan Venus orbits the Sun at an average distance of about 0.72 AU (108 million km; 67 million mi) with almost no eccentricity. In fact, with its farthest orbit (aphelion) of 0.728 AU (108,939,000 km) and closest orbit (perihelion) of 0.718 AU (107,477,000 km), it has the most circular orbit of any planet in the Solar System. The planet completes an orbit around the Sun every 224.65 days, meaning that a year on Venus is 61.5% as long as a year on Earth. When Venus lies between Earth and the Sun, a position known as inferior conjunction, it makes the closest approach to Earth of any planet, at an average distance of 41 million km. This takes place, on average, once every 584 days, and is the reason why Venus is the closest planet to Earth .

The planet completes an orbit around the Sun every 224.65 days, meaning that a year on Venus is 61.5% as long as a year on Earth. Unlike most other planets in the Solar System, which rotate on their axes in an counter-clockwise direction, Venus rotates clockwise (called “retrograde” rotation). It also rotates very slowly, taking 243 Earth days to complete a single rotation. This is not only the slowest rotation period of any planet, it also means that a single day on Venus lasts longer than a Venusian year. Venus’ atmosphere is also known to experience lightning storms . Since Venus does not experience rainfall (except in the form of sulfuric acid), it has been theorized that the lightning is being caused by volcanic eruptions. Several spacecraft have visited Venus, and a few landers have even made it to the surface to send back images of its hellish landscape. Even though there were made of metal, these landers only survived a few hours at best. Venus is made special by the fact that it is very much like Earth, but also radically different.

It’s thick atmosphere could crush a living being, its heat could melt lead, and its acid rain could dissolve flesh, bone and metal alike! It also rotates very slowly, and backwards relative to the other plants. Earth: Earth is our home, and the third planet from the Sun. With a mean radius of 6371 km and a mass of 5.97×1024 kg, it is the fifth largest and fifth most-massive planet in the Solar System. And with a mean density of 5.514 g/cm³, it is the densest planet in the Solar System. Like Mercury, Venus and Mars, Earth is a terrestrial planet. But unlike these other planets, Earth’s core is differentiated between a solid inner core and liquid outer core. The outer core also spins in the opposite direction as the planet, which is believed to create a dynamo effect that gives Earth its protective magnetosphere. Combined with a atmosphere that is neither too thin nor too thick, Earth is the only planet in the Solar System known to support life. The Earth’s layers, showing the Inner and Outer Core, the Mantle, and Crust.

Credit: discovermagazine.com In terms of its orbit, Earth has a very minor eccentricity (approx. 0.0167) and ranges in its distance from the Sun between 147,095,000 km (0.983 AU) at perihelion to 151,930,000 km (1.015 AU) at aphelion. This works out to an average distance (aka. semi-major axis) of 149,598,261 km, which is the basis of a single Astronomical Unit (AU) The Earth has an orbital period of 365.25 days, which is the equivalent of 1.000017 Julian years. This means that every four years (in what is known as a Leap Year), the Earth calendar must include an extra day. Though a single solar day on Earth is considered to be 24 hours long, our planet takes precisely 23h 56m and 4 s to complete a single sidereal rotation (0.997 Earth days).

Earth’s axis is also tilted 23.439281° away from the perpendicular of its orbital plane, which is responsible for producing seasonal variations on the planet’s surface with a period of one tropical year (365.24 solar days). In addition to producing variations in terms of temperature, this also results in variations in the amount of sunlight a hemisphere receives during the course of a year. Earth has only a single moon: the Moon . Thanks to examinations of Moon rocks that were brought back to Earth by the Apollo missions , the predominant theory states that the Moon was created roughly 4.5 billion years ago from a collision between Earth and a Mars-sized object (known as Theia ). This collision created a massive cloud of debris that began circling our planet, which eventually coalesced to form the Moon we see today. A picture of Earth taken by Apollo 11 astronauts. Credit: NASA What makes Earth special, you know, aside from the fact that it is our home and where we originated? It is the only planet in the Solar System where liquid, flowing water exists in abundance on its surface, has a viable atmosphere, and a protective magnetosphere.

In other words, it is the only planet (or Solar body) that we know of where life can exist on the surface. In addition, no planet in the Solar System has been studied as well as Earth, whether it be from the surface or from space. Thousands of spacecraft have been launched to study the planet, measuring its atmosphere, land masses, vegetation, water, and human impact. Our understanding of what makes our planet unique in our Solar System has helped in the search for Earth-like planets in other systems. Mars: The fourth planet from the Sun is Mars , which is also the second smallest planet in the Solar System. It has a radius of approximately 3,396 km at its equator, and 3,376 km at its polar regions – which is the equivalent of roughly 0.53 Earths. While it is roughly half the size of Earth, it’s mass – 6.4185 x 10²³ kg – is only 0.151 that of Earth’s. It’s density is also lower than Earths, which leads to it experiencing about 1/3rd Earth’s gravity (0.376 g).

It’s axial tilt is very similar to Earth’s, being inclined 25.19° to its orbital plane (Earth’s axial tilt is just over 23°), which means Mars also experiences seasons. Mars has almost no atmosphere to help trap heat from the Sun, and so temperatures can plunge to a low of -140 °C (-220 °F) in the Martian winter. However, at the height of summer, temperatures can get up to 20 °C (68 °F) during midday at the equator. However, recent data obtained by the Curiosity rover and numerous orbiters have concluded that Mars once had a denser atmosphere. Its loss, according to data obtained by NASA’s Mars Atmosphere and Volatile Evolution (MAVEN), the atmosphere was stripped away by solar wind over the course of a 500 million year period, beginning 4.2 billion years ago. At its greatest distance from the Sun (aphelion), Mars orbits at a distance of 1.666 AUs, or 249.2 million km.

At perihelion, when it is closest to the Sun, it orbits at a distance of 1.3814 AUs, or 206.7 million km. At this distance, Mars takes 686.971 Earth days, the equivalent of 1.88 Earth years, to complete a rotation of the Sun. In Martian days (aka. Sols, which are equal to one day and 40 Earth minutes), a Martian year is 668.5991 Sols. Like Mercury, Venus, and Earth, Mars is a terrestrial planet, composed mainly of silicate rock and metals that are differentiated between a core, mantle and crust. The red-orange appearance of the Martian surface is caused by iron oxide, more commonly known as hematite (or rust). The presence of other minerals in the surface dust allow for other common surface colors, including golden, brown, tan, green, and others. Although liquid water cannot exist on Mars’ surface, owing to its thin atmosphere, large concentrations of ice water exist within the polar ice caps – Planum Boreum and Planum Australe.

In addition, a permafrost mantle stretches from the pole to latitudes of about 60°, meaning that water exists beneath much of the Martian surface in the form of ice water. Radar data and soil samples have confirmed the presence of shallow subsurface water at the middle latitudes as well. MSL Curiosity selfie on the surface of Mars. Image: NASA/JPL/Cal-Tech Mars has two tiny asteroid-sized moons: Phobos and Deimos . Because of their size and shape, the predominant theory is that Mars acquired these two moons after they were kicked out of the Asteroid Belt by Jupiter’s gravity. Mars has been heavily studied by spacecraft. There are multiple rovers and landers currently on the surface and a small fleet of orbiters flying overhead. Recent missions include the Curiosity Rover, which gathered ample evidence on Mars’ water past, and the groundbreaking discovery of finding organic molecules on the surface . Upcoming missions include NASA’s InSight lander and the Exomars rover. Hence, Mars’ special nature lies in the fact that it also is terrestrial and lies within the outer edge of the Sun’s habitable zone.

And whereas it is a cold, dry place today, it once had an thicker atmosphere and plentiful water on its surface. Jupiter: Mighty Jupiter is the fouth planet for our Sun and the biggest planet in our Solar System . Jupiter’s mass, volume, surface area and mean circumference are 1.8981 x 1027 kg, 1.43128 x 1015 km3, 6.1419 x 1010 km2, and 4.39264 x 105 km respectively. To put that in perspective, Jupiter diameter is roughly 11 times that of Earth, and 2.5 times the mass of all the other planets in the Solar System combined. Jupiter has spectacular aurora, such as this view captured by the Hubble Space Telescope. Credit: NASA, ESA, and J. Nichols (University of Leicester) But, being a gas giant, it has a relatively low density – 1.326 g/cm3 – which is less than one quarter of Earth’s.

This means that while Jupiter’s volume is equivalent to about 1,321 Earths, it is only 318 times as massive. The low density is one way scientists are able to determine that it is made mostly of gases, though the debate still rages on what exists at its core (see below). Jupiter orbits the Sun at an average distance (semi-major axis) of 778,299,000 km (5.2 AU), ranging from 740,550,000 km (4.95 AU) at perihelion and 816,040,000 km (5.455 AU) at aphelion. At this distance, Jupiter takes 11.8618 Earth years to complete a single orbit of the Sun. In other words, a single Jovian year lasts the equivalent of 4,332.59 Earth days. However, Jupiter’s rotation is the fastest of all the Solar System’s planets, completing a rotation on its axis in slightly less than ten hours (9 hours, 55 minutes and 30 seconds to be exact).

Therefore, a single Jovian year lasts 10,475.8 Jovian solar days. This orbital period is two-fifths that of Saturn, which means that the two largest planets in our Solar System form a 5:2 orbital resonance. Much like Earth, Jupiter experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere create a light show that is truly spectacular. The Juno spacecraft isn’t the first one to visit Jupiter. Galileo went there in the mid 90’s, and Voyager 1 snapped a nice picture of the clouds on its mission. Credit: NASA Jupiter also experiences violent weather patterns . Wind speeds of 100 m/s (360 km/h) are common in zonal jets, and can reach as high as 620 kph (385 mph). Storms form within hours and can become thousands of km in diameter overnight. One storm, the Great Red Spot , has been raging since at least the late 1600s.

The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear . Jupiter is composed primarily of gaseous and liquid matter. It is the largest of the gas giants, and like them, is divided between a gaseous outer atmosphere and an interior that is made up of denser materials. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements. The interior contains denser materials, such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass. It is believed that Jupiter’s core is a dense mix of elements – a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. The core has also been described as rocky, but this remains unknown as well.

Jupiter has been visited by several spacecraft, including NASA’s Pioneer 10 and Voyager spacecraft in 1973 and 1980, respectively; and by the Cassini and New Horizons spacecraft more recently. Until the recent arrival of Juno , only the Galileo spacecraft has ever gone into orbit around Jupiter, and it was crashed into the planet in 2003 to prevent it from contaminating one of Jupiter’s icy moons. Illustration of Jupiter and the Galilean satellites. Credit: NASA In short, Jupiter is massive and has massive storms. But compared to the planets of the inner Solar System, is it significantly less dense. Jupiter also has the most moons in the Solar System, with 67 confirmed and named moons orbiting it. But it is estimated that as many as 200 natural satellites may exist around the planet. Little wonder why this planet is named after the king of the gods. Saturn: Saturn is the second largest planet in the Solar System. With a mean radius of 58232±6 km, it is approximately 9.13 times the size of Earth.

And at 5.6846×1026 kg, it is roughly 95.15 as massive. However, since it is a gas giant, it has significantly greater volume – 8.2713×1014 km3, which is equivalent to 763.59 Earths. The sixth most distant planet, Saturn orbits the Sun at an average distance of 9 AU (1.4 billion km; 869.9 million miles). Due to its slight eccentricity, the perihelion and aphelion distances are 9.022 (1,353.6 million km; 841.3 million mi) and 10.053 AU (1,513,325,783 km; 940.13 million mi), on average respectively. With an average orbital speed of 9.69 km/s, it takes Saturn 10,759 Earth days to complete a single revolution of the Sun. In other words, a single Cronian year is the equivalent of about 29.5 Earth years.

However, as with Jupiter, Saturn’s visible features rotate at different rates depending on latitude, and multiple rotation periods have been assigned to various regions. This portrait looking down on Saturn and its rings was created from images obtained by NASA’s Cassini spacecraft on Oct. 10th, 2013. Credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic As a gas giant, Saturn is predominantly composed of hydrogen and helium gas. With a mean density of 0.687 g/cm3, Saturn is the only planet in the Solar System that is less dense than water; which means that it lacks a definite surface, but is believed to have a solid core. This is due to the fact that Saturn’s temperature, pressure, and density all rise steadily toward the core. Standard planetary models suggest that the interior of Saturn is similar to that of Jupiter, having a small rocky core surrounded by hydrogen and helium with trace amounts of various volatiles. This core is similar in composition to the Earth, but more dense due to the presence of metallic hydrogen, which as a result of the extreme pressure.

As a gas giant, the outer atmosphere of Saturn contains 96.3% molecular hydrogen and 3.25% helium by volume. Trace amounts of ammonia, acetylene, ethane, propane, phosphine and methane have been also detected in Saturn’s atmosphere. Like Jupiter, it also has a banded appearance, but Saturn’s bands are much fainter and wider near the equator. On occasion, Saturn’s atmosphere exhibits long-lived ovals that are thousands of km wide, similar to what is commonly observed on Jupiter. Whereas Jupiter has the Great Red Spot, Saturn periodically has what’s known as the Great White Spot (aka. Great White Oval). This unique but short-lived phenomenon occurs once every Saturnian year, roughly every 30 Earth years, around the time of the northern hemisphere’s summer solstice. The huge storm churning through the atmosphere in Saturn’s northern hemisphere overtakes itself as it encircles the planet in this true-color view from NASA’s Cassini spacecraft. Image credit: NASA/JPL-Caltech/SSI The persisting hexagonal wave pattern around the north pole was first noted in the Voyager images.

The sides of the hexagon are each about 13,800 km (8,600 mi) long (which is longer than the diameter of the Earth) and the structure rotates with a period of 10h 39m 24s, which is assumed to be equal to the period of rotation of Saturn’s interior. The south pole vortex, meanwhile, was first observed using the Hubble Space Telescope . These images indicated the presence of a jet stream, but not a hexagonal standing wave. These storms are estimated to be generating winds of 550 km/h, are comparable in size to Earth, and believed to have been going on for billions of years. In 2006, the Cassini space probe observed a hurricane-like storm that had a clearly defined eye. Such storms had not been observed on any planet other than Earth – even on Jupiter. Of course, the most amazing feature of Saturn is its rings . These are made of particles of ice ranging in size from a grains of sand to the size of a car. Some scientists think the rings are only a few hundred million years old, while others think they could be as old as the Solar System itself.

Saturn has been visited by spacecraft 4 times: Pioneer 11 , Voyager 1 and 2 were just flybys, but Cassini has actually gone into orbit around Saturn and has captured thousands of images of the planet and its moons. And speaking of moons, Saturn has a total of 62 moons discovered (so far), though estimates indicate that it might have as many as 150. A collage of Saturn (bottom left) and some of its moons: Titan, Enceladus, Dione, Rhea and Helene. Credit: NASA/JPL/Space Science Institute So like Jupiter, Saturn is a massive gas giant that experiences some very interesting weather patterns. It also has lots of moons and has a very low density. But what really makes Saturn stand out is its impressive ring system. Whereas every gas and ice giant has one, Saturn’s is visible to the naked eye and very beautiful to behold! Uranus: Next comes Uranus , the seventh planet from the Sun.

With a mean radius of approximately 25,360 km and a mass of 8.68 × 1025 kg, Uranus is approximately 4 times the sizes of Earth and 63 times its volume. However, as a gas giant, its density (1.27 g/cm3) is significantly lower; hence, it is only 14.5 as massive as Earth. The variation of Uranus’ distance from the Sun is also greater than that any other planet (not including dwarf planets or plutoids). Essentially, the gas giant’s distance from the Sun varies from 18.28 AU (2,735,118,100 km) at perihelion to 20.09 AU (3,006,224,700 km) at aphelion. At an average distance of 3 billion km from the Sun, it takes Uranus roughly 84 years (or 30,687 days) to complete a single orbit of the Sun.

The standard model of Uranus’s structure is that it consists of three layers: a rocky (silicate/iron–nickel) core in the center, an icy mantle in the middle and an outer envelope of gaseous hydrogen and helium. Much like Jupiter and Saturn, hydrogen and helium account for the majority of the atmosphere – approximately 83% and 15% – but only a small portion of the planet’s overall mass (0.5 to 1.5 Earth masses). Uranus as seen through the automated eyes of Voyager 2 in 1986. (Credit: NASA/JPL) The third most abundant element is methane ice (CH4), which accounts for 2.3% of its composition and which accounts for the planet’s aquamarine or cyan coloring. Trace amounts of various hydrocarbons are also found in the stratosphere of Uranus, which are thought to be produced from methane and ultraviolent radiation-induced photolysis. They include ethane (C2H6), acetylene (C2H2), methylacetylene (CH3C2H), and diacetylene (C2HC2H).

In addition, spectroscopy has uncovered carbon monoxide and carbon dioxide in Uranus’ upper atmosphere, as well as the presence icy clouds of water vapor and other volatiles , such as ammonia and hydrogen sulfide. Because of this, Uranus and Neptune are considered a distinct class of giant planet – known as “Ice Giants” – since they are composed mainly of heavier volatile substances. The rotational period of the interior of Uranus is 17 hours, 14 minutes. As with all giant planets, its upper atmosphere experiences strong winds in the direction of rotation. Hence its weather systems are also broken up into bands that rotate around the planet, which are driven by internal heat rising to the upper atmosphere. As a result, winds on Uranus can reach up to 900 km/h (560 mph), creating massive storms like the one spotted by the Hubble Space Telescope in 2012. Similar to Jupiter’s Great Red Spot, this “ Dark Spot ” was a giant cloud vortex that measured 1,700 kilometers by 3,000 kilometers (1,100 miles by 1,900 miles). Huge storms on Uranus were spotted by the Keck Observatory on Aug.

5 and Aug. 6, 2014. Credit: Imke de Pater (UC Berkeley), Pat Fry (University of Wisconsin), Keck Observatory One unique feature of Uranus is that it rotates on its side. Whereas all of the Solar System’s planets are tilted on their axes to some degree, Uranus has the most extreme axial tilt of 98°. This leads to the radical seasons that the planet experiences, not to mention an unusual day-night cycle at the poles. At the equator, Uranus experiences normal days and nights; but at the poles, each experience 42 Earth years of day followed by 42 years of night. Uranus was the first planet to be discovered with a telescope; it was first recognized as a planet in 1781 by William Herschel. Beyond Earth-based observations, only one spacecraft (Voyager 2) has ever studied Uranus up close. It passed by the planet in 1986, and captured the first close images. Uranus has 27 known moons . Uranus’ special nature comes through in its natural beauty, its intense weather, its ring system and its impressive array of moons.

And it’s compositions, being an “ice” giant, is what gives its aquamarine color. But perhaps mist interesting is its sideways rotation, which is unique among the Solar planets. Neptune: Neptune is the 8th and final planet in the Solar System, orbiting the Sun at a distance of 29.81 AU (4.459 x 109 km) at perihelion and 30.33 AU (4.537 x 109 km) at aphelion. With a mean radius of 24,622 ± 19 km, Neptune is the fourth largest planet in the Solar System and four times as large as Earth. But with a mass of 1.0243×1026 kg – which is roughly 17 times that of Earth – it is the third most massive, outranking Uranus. Neptune’s system of moons and rings visualized. Credit: SETI Neptune takes 16 h 6 min 36 s (0.6713 days) to complete a single sidereal rotation, and 164.8 Earth years to complete a single orbit around the Sun.

This means that a single day lasts 67% as long on Neptune, whereas a year is the equivalent of approximately 60,190 Earth days (or 89,666 Neptunian days). Due to its smaller size and higher concentrations of volatiles relative to Jupiter and Saturn, Neptune (much like Uranus) is often referred to as an “ice giant” – a subclass of a giant planet. Also like Uranus, Neptune’s internal structure is differentiated between a rocky core consisting of silicates and metals; a mantle consisting of water, ammonia and methane ices; and an atmosphere consisting of hydrogen, helium and methane gas. The core of Neptune is composed of iron, nickel and silicates, with an interior model giving it a mass about 1.2 times that of Earth. The pressure at the center is estimated to be 7 Mbar (700 GPa), about twice as high as that at the center of Earth, and with temperatures as high as 5,400 K. At a depth of 7000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones.

Because Neptune’s axial tilt (28.32°) is similar to that of Earth (~23°) and Mars (~25°), the planet experiences similar seasonal changes. Combined with its long orbital period, this means that the seasons last for forty Earth years. Also owing to its axial tilt being comparable to Earth’s is the fact that the variation in the length of its day over the course of the year is not any more extreme than it on Earth. Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL Just like Jupiter and Saturn, Neptune has bands of storms that circle the planet. Astronomers have clocked winds on Neptune traveling at 2,100 km/hour, which is believed to be due to Neptune’s cold temperatures – which may decrease the friction in the system, During its 1989 flyby, NASA’s Voyager 2 spacecraft discovered the Great Dark Spot on Neptune. Similar to Jupiter’s Great Red Spot, this is an anti-cyclonic storm measuring 13,000 km x 6,600 km across.

A few years later, however, the Hubble Space Telescope failed to see the Great Dark Spot, but it did see different storms. This might mean that storms on Neptune don’t last as long as they do on Jupiter or even Saturn. The more active weather on Neptune might be due, in part, to its higher internal heat. Although Neptune is much more distant than Uranus from the Sun, receiving 40% less sunlight, temperatures on the surface of the two planets are roughly similar. In fact, Neptune radiates 2.61 times as much energy as it receives from the Sun. This is enough heat to help drive the fastest winds in the Solar System. Neptune is the second planet discovered in modern times. It was discovered at the same time by both Urbain Le Verrier and John Couch Adams. Neptune has only ever been visited by one spacecraft, Voyager 2, which made a fly by in August, 1989. Neptune has 13 known moons . Th largest and most famous of these is Triton , which is believed to be a former KBO that was captured by Neptune’s gravity. Global Color Mosaic of Triton, taken by Voyager 2 in 1989.

Credit: NASA/JPL/USGS So much like Uranus, Neptune has a ring system, some intense weather patterns, and an impressive array of moons. Also like Uranus, Neptune’s composition allows for its aquamarine color; except that in Neptune’s case, this color is more intense and vivid. In addition, Neptune experiences some temperature anomalies that are yet to be explained. And let’s not forgt the raining diamonds! And those are the planets in the Solar System thank you for joining the tour! Unfortunately, Pluto isn’t a planet any more, hence why it was not listed. We know, we know, take it up with the IAU! Planets Planets Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune |* Pluto Traditional Definition Etymology: Middle English planete, from Old French, from Late Latin planeta, modification of Greek planEt-, planEs, literally, wanderer, from planasthai to wander. any of the seven celestial bodies: Sun, Moon, Venus, Jupiter, Mars, Mercury, and Saturn that in ancient belief have motions of their own among the fixed stars. any of the large bodies that revolve around the Sun in the solar system.

[see IAU resolutions below] a similar body associated with another star. EARTH -- usually used with "the". a celestial body held to influence the fate of human beings a person or thing of great importance : LUMINARY - plan�et�like /-"lIk/ adjective * The IAU [ International Astronomical Union ] officially designates planets within our solar system. STATUS February 2, 2006 "The IAU notes the very rapid pace of discovery of bodies within the Solar system over the last decade and so our understanding of the Trans-Neptunian Region is therefore still evolving very rapidly. This is in serious contrast to the situation when Pluto was discovered. As a consequence, The IAU has established a Working Group to consider the definition of a minimum size for a Planet.

Until the report of this Working Group is received, all objects discovered at a distance from the Sun greater than 40 AU will continue to be regarded as part of the Trans-Neptunian population." UPDATE August 24, 2006 RESOLUTION 5A The IAU therefore resolves that planets and other bodies in our Solar System be defined into three distinct categories in the following way: (1) A planet1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. (2) A dwarf planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. (3) All other objects3 orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. 2An IAU process will be established to assign borderline objects into either dwarf planet and other categories. 3These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies. Relative sizes of the planets and stars by Dave Jarvis . Smallest Planets The Solar System The Solar System Our Solar System is an amazing place. Not only is it home to eight planets, it also hold several dwarf planets, hundreds of moons, and thousands of stars and asteroids. The eight planets in our Solar System are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. These planets orbit the Sun. Here is a funny song to help you remember the planets The Sun The Sun is the center of our Solar System. It is because of the Sun that our solar system gets its name. Sol is the Roman name for Sun. The Sun is the largest object within the Solar System - it makes up more than 95% of all the matter!

It is because of the Sun's large size that the rest of the objects within the Solar System orbit around it. The Sun is very, very hot. It is 10,000 degrees Fahrenheit on its surface. Mercury Mercury is the closest planet to the Sun, making it the first planet in the Solar System. It is named after the Roman messenger god. In mythology, the god was known for being quick - Mercury is the fastest of all the planets to orbit the Sun, because it has the smallest route it has to take! Mercury can occasionally be seen from Earth Mercury is the second densest planet in the Solar System It is mainly made up of iron There is no atmosphere on Mercury Despite its fast trip around the Sun, Mercury's revolution is very slow - one day on Mercury equals about 59 days on Earth! Venus Venus is the second planet from the Sun. It is named after the Roman goddess of beauty and love. Venus is almost the same size as Earth, but other than size the two planets are very different! Fun Facts about Venus Venus appears to be the brightest planet in the sky due to the reflection of the Sun from its clouds, and its closeness to Earth Venus has an incredibly thick atmosphere.

This makes it the hottest of the inner planets Venus rotates East to West Venus is covered in volcanoes Venus does not have any moons Earth Earth is the only known planet that has any life forms in the Solar System. It is the third planet from the Sun. It is the only planet that is not named after a god. Most of the Earth is covered in water - 70%! Earth has a thin atmosphere, that protects us from dangerous gasses and heat in space Earth is the largest of the inner planets Air, water, and land make up the Earth Earth's axis is tilted at 23.5 degrees This a video showing the many different life forms that Earth has Mars Mars is the fourth planet from the Sun. Named for the Roman god of war, it is also known as the "Red Planet". It is the last of the inner planets. Temperatures on Mars are very similar to temperatures on Earth It is believed that Mars once had water on its surface Mars is called the red planet because its surface is covered in red dust The largest volcano in the Solar System is on Mars. It is called Olympus Mons Mars has two small moons Jupiter Jupiter is the first of the outer planets, and the fifth planet from the Sun.

It is named for the king of the Roman gods. It is the largest of all of the planets. Fun Facts about Jupiter Jupiter is best known for its "Great Red Spot" - a mass of hurricanes that have been storming for hundreds of years. The spot is larger in size than that of Earth Jupiter is made up of gasses - there is no solid surface on it Jupiter is so big; Earth could fit inside of it more than 1,000 times! Jupiter has over 50 moons. Four of these moons are as big as planets Jupiter has the most active volcanic activity in the Solar System Learn more about the Great Red Spot! Saturn Saturn is the sixth planet from the Sun. It is named for the Roman god of agriculture. It is most well known for its highly visible rings. Other Features of the Solar System There are many other exciting elements in the Solar System. Here are a few. Asteroids Asteroids are rocky bodies in the Solar System that are too small to be considered actual planets. In between Mars and Jupiter lies the Asteroid Belt, containing well over 90,000 asteroids. Comets Comets are ice and rock that grow tails the closer they get to the sun.

The hotter they get, the longer this "tail" becomes. The sunlight makes comets glow, which causes them to be visible on Earth. Dwarf Planets Dwarf planets are bodies that orbit the sun that are not considered large enough to be actual planets. The most famous dwarf planet is Pluto, which was considered an actual planet up until 2006. Satellites Satellites are machines put into the Solar System by scientists in order to find out more about the Solar System, and what is in it. These machines take pictures, perform experiments, take data, and much, much more. Without them, we wouldn't have the vast amount of information that we have today. Summary The Solar System is a fascinating place. Each of the eight planets have their own unique features, but are also similar in some ways - much like people! It is amazing to think that the Solar System has been around for more than 4.6 billions years. Each of the eight planets orbits the sun in the same direction, and in their own time. We have so much more we can learn about the Solar System, and so much we have learned already today. sit this page to learn more interesting facts about the Solar System!

Want to get an idea of how far apart the planets are? Click here! Resources Our Solar System. Retrieved from Solar System. Retrieved from uranus,, the third largest planet in our solar system and the seventh planet farthest from the sun ~ Planetary science Period of rotation around the sun 84.01 Earth years Rotation around the same period (day on Uranus) 17.9 hour ground Planet Uranus is the third largest planet in our solar system and the seventh planet farthest from the sun, was discovered in 1781 by the world William Herchil, a gas giant like Jupiter and Saturn, consists mostly of methane and ethane.

Shows the planet green and blue due to the withdrawal of methane formed in the atmosphere top, which gives it the color and because methane restricts red light does not allow for that color to escape, and dragging dense covering landmarks surface of procedure, and emphasizes color planet italics blue light the fact that it covered clouds, and to by Guillaume crystals of methane in the atmosphere there is fog composed of ethane at high levels in the atmosphere, clouds molecules constantly repeats itself, first formed and then crash heavier crystals, an indication that the atmosphere of Uranus is still evolving since it was formed out of the solar nebula. Because that Uranus is based on his part, he very strange seasons, the movements of the clouds indicate that, like Jupiter and Saturn, basic weather Uranus can be described as a module of the wind lines, this means that Uranus like Jupiter and Saturn.

Internal structure Internal structure of Uranus is composed mainly of methane in the form of snow, and begins ice formation in the atmosphere of Uranus, near layer clouds of methane, and continue the amount of snow in the air growing, even up to layer melting snow and then snow steel, this snow is warm and can flow like rocks in internal mantle layer of the planet Earth.Compared with Jupiter and Saturn, Uranus has a little more metal hydrogen them, and there are a lot more snow, where the magnetosphere is generated from the metal layer, which means that Uranus must have a much smaller magnetic casing from the buyer.Center Uranus component elements heavy metal and rock, when formed planets from the cloud solar, cutting heavy rocks gathered inside the planet formed, and when he finished the planet formed, centered these pieces of heavy rocks in the middle of the planet, and ultimately material rocky heavy in the center became the heart.Inside Uranus, ice layers warm enough to move and flow from the inside out, some scientists believe that within Uranus probably has a different type of movement.

Atmosphere of the planetThe gaseous part of the planet was much larger than the rocky part, due to the amount of gas and ice that came to Uranus initially relied on Uranus in place original solar Cloud. The residual heat from the process of forming Uranus possible it currently affecting movements in the atmosphere of Uranus.The climate in Uranus follow the way of violation of the land where the North Pole of the planet facing the sun during the half-year (spring and summer) to arrive at the air warm and moving to place the coldest face Antarctic cold Unlike Earth, which starts wind from the equator Dafi and facing the sun and heading to polarity colder. Therefore, the planet's North Pole always corresponds to the sun.Rings of UranusLike the rest of the other gaseous planets, has Uranus rings, a dark but like Saturn is composed of large molecules, which range up to 10 meters in diameter in addition to light dust.Known as one of the ten ring of Uranus, all very faint rings; and brightest ring known as Upsilon Epsilon.

The rings of Uranus first after Saturn that had been explored, which was important and made us know that the rings are not a feature of Saturn alone, but the rest of the gaseous planets. MagnetosphereMagnetosphere of a planet Uranus average size, but it's still much larger than the Earth's magnetic, each carrying satellites of Uranus, might be expected to be in the middle of the planet and ice instead of iron in the heart, and it seems that this magnetosphere produces movements of layered ice inside the planet.The planet's magnetosphere has a tendency very strange. Radical tendency, combined with the extreme tendency to Uranus itself, make it this strange magnetosphere, which has a quirky structure.Believes mathematical theories that the rings of Uranus pulls particles in the magnetosphere into the atmosphere. The internal structure of the planet Rings planet Lawrence The Solar System's Twenty Largest Objects - Bob the Alien's Tour of the Solar System Solar System Formation The Inner Planets The Outer Planets Inner & Outer Planets Planetary Statistics Table 20 Largest Objects The Solar System's Twenty Largest Objects Greetings, planet pickers! Welcome to Bob the Alien's Top of the Solar System!

The Solar System is full of thousands of objects of various shapes and sizes - some unimaginably huge and some extremely tiny. Here is our rundown of the twenty largest items in the Solar System. WIDTH ACROSS EQUATER AND LOCATION Yellow dwarf star, centre of the Solar System Topping our charts for what seems like an eternity and the undisputed holder of the title of Official Largest Object in the Solar System is everybody's favourite star, the Sun ! At a width of 1,392,000 km (865,000 miles) and weighing in at 1,989,000,000,000,000,000,000,000,000,000 kilograms (whoever weighed it must have some pretty big scales!), the Sun is large enough to contain every single other object in the Solar System and is set to get even bigger as it gets older. It is almost ten times wider than the next largest object in the Solar System, which is...... The Sun AND LOCATION Gas Giant. Fifth planet from the Sun, first of the Outer Planets By Jove, it's Jupiter !

Yes, second in our chart is the Solar System's largest planet and the first of the Gas Giants . Jupiter is a world made mostly of gas (hydrogen and helium if you're interested), hence the reason why it's called a Gas Giant . Scientists think that it may have a solid core surrounded by liquid metallic oceans, but they don't know for sure. In fact, they're probably just guessing. It could have a chocolate centre for all they know. Jupiter is a stormy world, with one storm in particular - The Great Red Spot - having raged for at least four hundred years. Keeping Jupiter company are at least 63 moons . Don't be surprised if some of them pop up later in this list. WIDTH ACROSS EQUATER AND LOCATION Gas Giant. Sixth planet from the Sun, second of the Outer Planets Jupiter's not-so-near neighbour is Saturn and it takes bronze position in this leaderboard of the Solar System's giants. Whoever or whatever created the Solar System seemed to like Saturn so much that they put a ring on it! With a similar gassy composition to Jupiter , Saturn also has a multitude of moons of all shapes and sizes orbiting it.

Its diameter is 120,536 kilometres (74,900 miles), but if we take into consideration its ringspan, Saturn's diameter more than doubles to a whopping 270,000 kilometres (168,000 miles). Saturn AND LOCATION Gas Giant. Seventh planet from the Sun, third of the Outer Planets Fourth on our list is the rather dull and featureless Uranus . But what it lacks it looks, it makes up in peculiarity. At some point in its history, Uranus fell over. Either this was because another large object collided with it and knocked it over, or it just felt like being different. Whatever happened, Uranus appears to orbit on its side , as if it is rolling around the Sun . Scientists are easily excitable creatures, and the effects of Uranus ' sideways orbit excites them greatly. You see, its orbit causes Uranus to have an 'interesting' magnetic field, day and night to last forever (42 years), and its moons to orbit up and under the planet. WIDTH ACROSS EQUATER CLASSIFICATION AND LOCATION Gas Giant.

Eighth and most distant regular planet from the Sun, fourth of the Outer Planets When it was discovered in 1851, Neptune , the fifth object on our list, was the most distant planet in the Solar System. It lost its claim to this title in 1930 when Pluto was discovered, briefly regaining it for a few years in the late 1990s due to Pluto's weird orbit. However, when Pluto was permanently thrown out of the Planet Gang* in 2006 for being too strange, Neptune was once again given the title of Official Most Distant Planet in the Solar System (remember that if you're doing 'space travel brochures' kids!). Neptune is the last of the Gas Giants , representing the end of the region of the Solar System dominated by the huge gassy worlds. *Note: The Planet Gang doesn't actually exist. I just made it up. Neptune AND LOCATION Inner Planet. Third planet from the Sun At number six is the Solar System's most unique, most special and most interesting object. It's none other than your home. Well, obviously, not your actual house, but the world on which it is situated.

It's Earth , the first object in this chart with a solid surface, and therefore the first place you can actually stand on. The presence of water on its surface, a breathable atmosphere, a suitable climate and protection from the Sun's dangerous rays are all factors that allow Earth to be the ideal place for life. The planet is now home to countless lifeforms, and you are of course one of them! But, take care of Earth , because there's nowhere else to go. WIDTH ACROSS EQUATER AND LOCATION Inner Planet. Second planet from the Sun With a size, mass, gravity and composition similar to Earth , Venus is often seen as its slightly smaller twin. If it is Earth's twin , Venus is most definitely an evil one. Something went drastically wrong with Venus at some point. If you were able to stand on its surface , you would be crushed, suffocated, cooked and pretty much doomed. Venus' surface pressure is similar to being 1km below water on Earth. Its atmosphere contains poisonous carbon dioxide, clouds contain sulphuric acid and temperatures are almost 500 ï¿½C (900 ï¿½F), hot enough to melt lead.

And, even if you could survive, the fact that a day on Venus is longer than its year, and that it spins the wrong way, will just mess with your head! It's little wonder that Venus hides it horrors under a cover of deceptively beautiful clouds. Venus AND LOCATION Inner Planet. Fourth planet from the Sun. Now this is more like it! Forget Venus and its inhospitality. Mars is much more accommodating, and over the years, the Red Planet has welcomed visitors aplenty , allowing rovers to drive across its surface, take pictures, poke its rocks and analyse its soil. Even so, it's still not somewhere that you'd go to in a hurry. With an unbreathable atmosphere, no water to drink (well, perhaps a small amount) and temperatures that are chilly to the extreme, Mars is not really the best place for a day out. That's not to say that life over there has been completely ruled out. Scientists continue to find evidence that could suggest that life could be or could have been possible on Mars . WIDTH ACROSS EQUATER AND LOCATION Moon of Jupiter.

Eighth closest moon to Jupiter, third of the Galilean satellites Unbelievably, the ninth and tenth largest objects in the Solar System happen to be moons. Well, I found it quite unbelievable when I found out. The Solar System's largest moon is Ganymede which orbits the Solar System's largest planet, Jupiter . Large enough to have been spotted by Galileo Galilei in 1610 through one of the first telescopes, Ganymede's surface is a mixture of extremely ancient and slightly less extremely ancient. Part of it is heavily cratered, much like many moons, whereas other parts are much smoother, suggesting that some sort of geological disturbance occurred after the period of heavy bombardment. Scientists reckon that deep below the surface, there may be water. Ganymede AND LOCATION Moon of Saturn. Twenty-first moon in orbit of the planet The tenth largest object in the Solar System is Titan , the Solar System's second largest moon which orbits the Solar System's second largest planet, Saturn . What makes Titan unique is that it is the only moon in the Solar System to possess an atmosphere. And what an atmosphere it does possess!

In fact, to be able to see through it, a probe had to be send to its surface to take pictures. Images sent back from the Huygens probe which landed in 2005 - along with radar imagery from the Cassini orbiter - revealed Titan to possess lakes of liquid methane. As well as methane in its atmosphere and frozen methane on its surface, the element plays a similar role on Titan as water does on Earth . Scientists sometimes consider Titan to be similar to an early Earth and some even consider the possibility of life there. WIDTH ACROSS EQUATER AND LOCATION Moon of Jupiter. Fifth closest moon to Jupiter, first of the Galilean satellites Io , Io , it's off the Jupiter we go - again. The thirteenth largest object in the Solar System is Io , Jupiter's third largest moon and the closest of the four large Galilean satellites to orbit the planet. Io is a violent world where volcanoes erupt on a daily basis. The insides of Io are constantly churned and heated by the gravitational tug-of-war between Jupiter on one side and Europa , Ganymede and Callisto on the other.

The resulting eruptions give the moon an ever-changing colourful appearance, and the discovery of active volcanoes there in 1979 revealed that Earth isn't the only only geologically active place in the Solar System, a discovery that undoubtedly excited many scientists. Io AND LOCATION Natural satellite. In orbit of Earth Next up is a very familiar face - Earth's Moon , or Luna if you want to give it its proper name. Thought to have formed out of the debris from a collision of a planet-sized object with Earth in the early days of the Solar System, the Moon is 400 times smaller than the Sun but, by some bizarre coincidence, is 400 times closer to Earth than the Sun . This means that the Moon and the Sun appear to be the same size from Earth and that the Moon can completely cover the Sun's disc during a total eclipse . The Moon is the only surface other than Earth to have been stepped on by human beings. The last one there stepped off it in 1972, and it doesn't look like anybody will be back in the near future. WIDTH ACROSS EQUATER AND LOCATION Moon of Jupiter.

Sixth closest moon to Jupiter, second of the Galilean satellites It's back to Jupiter for the final time, and time to acquaint ourselves with Europa . Unlike most moons, Europa's surface is smooth. This is because its surface is ice. It is thought that the ice is as much as 30 kilometres thick (18 miles) and that below it there may be water. As you know, or you should if you've read this website properly seeing as I keep harping on about it, water is essential for life. As Europa is thought to be covered in it, scientists are especially eager to investigate it. Who knows what kind of mysterious sea-dwelling creatures lurk in the depths of Europa's oceans? Not me, that's for sure. Europa AND LOCATION Dwarf planet/Trans-Neptunian Object/Kuiper Belt Object/Plutoid. Most distant Dwarf planet in Solar System. The newest entry in our chart, Eris ' discovery in 2003 gave scientists headaches and many sleepless nights, resulting in catastrophe for Pluto . Being large and round, Eris , by definition, should have been a planet.

But, astronomers around the world didn't want Eris to be a planet for reasons best explained elsewhere ( here for example! ) so they voted to change the definition of a planet. A new definition - the dwarf planet - was created for worlds just like Eris , would-be planets that exist in regions shared with other objects. Eris became one of the first dwarf planets. But so did Pluto , losing its status as planet and angering many a scientist and people from Illinois. Eris AND LOCATION Dwarf planet/Trans-Neptunian Object/Kuiper Belt Object/Plutoid. Usually orbits beyond Neptune As if losing its status as a planet wasn't bad enough because of it, Eris ' discovery also resulted in Pluto dropping a place in this chart. Pluto was discovered in 1930 by Clyde Tombaugh who was looking for a large planet beyond Neptune that was affecting Uranus ' orbit. It later became apparent Uranus ' orbit was not actually being affected by anything beyond Neptune , so Pluto's discovery was more through pure luck than anything else. Pluto's name was suggested by an English schoolgirl. From its discovery up to 2006, Pluto was the ninth planet in the Solar System.

Nowadays, it is the Solar System's second largest dwarf planet . WIDTH ACROSS EQUATER

Question: What is the third largest planet in the Solar System?
Answer: Uranus